Abaixo está uma instrução que descreve uma tarefa de geração de SQL, combinada com uma entrada que fornece mais contexto sobre os esquemas de tabela disponíveis. Escreva o código SQL que responda adequadamente à solicitação
 ###Instrução: Error code: 429 - {'error': {'message': 'You exceeded your current quota, please check your plan and billing details. For more information on this error, read the docs: https://platform.openai.com/docs/guides/error-codes/api-errors.', 'type': 'insufficient_quota', 'param': None, 'code': 'insufficient_quota'}}
 ###Tabelas: 
CREATE TABLE farmers (id INT, name VARCHAR(255), system_type VARCHAR(255)); INSERT INTO farmers (id, name, system_type) VALUES (1, 'Jane Doe', 'Urban Agriculture'); INSERT INTO farmers (id, name, system_type) VALUES (2, 'John Smith', 'Agroecology'); INSERT INTO farmers (id, name, system_type) VALUES (3, 'Maria Garcia', 'Indigenous Food Systems'); INSERT INTO farmers (id, name, system_type) VALUES (4, 'Ali Ahmed', 'Urban Agriculture'); CREATE TABLE farmer_revenue (farmer_id INT, revenue FLOAT); INSERT INTO farmer_revenue (farmer_id, revenue) VALUES (1, 12000.00); INSERT INTO farmer_revenue (farmer_id, revenue) VALUES (2, 9000.00); INSERT INTO farmer_revenue (farmer_id, revenue) VALUES (3, 8500.00); INSERT INTO farmer_revenue (farmer_id, revenue) VALUES (4, 15000.00);
SELECT farmers.name, MAX(farmer_revenue.revenue) as highest_revenue FROM farmers JOIN farmer_revenue ON farmers.id = farmer_revenue.farmer_id WHERE farmers.system_type = 'Urban Agriculture' GROUP BY farmers.name;